运营环境作用对跨海大桥模态频率的影响研究
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摘要
模态频率是反映结构整体性能的动力学指标之一,然而实践中发现,即使结构性能正常,它也会随运营环境作用发生可观的变化。因此有必要研究运营环境作用与结构频率的相关性,以便从频率的总变化中剔除正常变化,凸显由结构损伤引起的频率变化。利用东海大桥的长期监测数据,该文同时分析了桥梁高阶频率和低阶频率的变化规律。在运营条件下,东海大桥的高阶频率和低阶频率均存在周期变化特征,且与运营环境因素的变化周期相吻合;结构温度和交通荷载是引起频率变化的最主要因素,温度与各阶频率的变化均呈负相关关系,而交通荷载与高阶频率的相关性不同于低阶频率。
The modal frequency is a commonly used index to reflect the global condition of a bridge. However, the field measurements have shown that the modal frequency would vary significantly with the operational and environmental actions, even if the bridge is in a good condition. Hence, it is necessary to investigate the action-frequency correlation of bridges in order to eliminate the normal frequency variation and then highlight the anomaly-induced frequency changes. Based on long-term monitoring data, this study simultaneously examined the periodic variability of the high-and low-order frequencies of Donghai Bridge. The periodic characteristics exist in the variation of both the high-and low-order frequencies, and the dominant cycles of modal frequencies coincide with those of the operational and environmental actions. The structural temperature and traffic loading exert a larger influence on frequency changes than the other actions. All the modal frequencies of Donghai Bridge have a negative correlation with the temperature change, while the correlation between frequencies and traffic loading seems to depend on the order of each mode.
The modal frequency is a commonly used index to reflect the global condition of a bridge. However, the field measurements have shown that the modal frequency would vary significantly with the operational and environmental actions, even if the bridge is in a good condition. Hence, it is necessary to investigate the action-frequency correlation of bridges in order to eliminate the normal frequency variation and then highlight the anomaly-induced frequency changes. Based on long-term monitoring data, this study simultaneously examined the periodic variability of the high-and low-order frequencies of Donghai Bridge. The periodic characteristics exist in the variation of both the high-and low-order frequencies, and the dominant cycles of modal frequencies coincide with those of the operational and environmental actions. The structural temperature and traffic loading exert a larger influence on frequency changes than the other actions. All the modal frequencies of Donghai Bridge have a negative correlation with the temperature change, while the correlation between frequencies and traffic loading seems to depend on the order of each mode.
引文
[1]Xia Y,Chen B,Weng S,et al.Temperature effect on vibration properties of civil structures:A literature review and case studies[J].Journal of Civil Structural Health Monitoring,2012,2(1):29―46.
[2]Mosavi A A,Seracino R,Rizkalla S.Effect of temperature on daily modal variability of a steel-concrete composite bridge[J].Journal of Bridge Engineering,2012,17(6):979―983.
[3]He X.Vibration-based damage identification and health monitoring of civil structures[D].San Diego:University of California,San Diego,2008.
[4]Cross E J,Koo K Y,Brownjohn J M W,et al.Long-term monitoring and data analysis of the tamar bridge[J].Mechanical Systems and Signal Processing,2013,35(1–2):16―34.
[5]Zhou H,Ni Y,Ko J.Eliminating temperature effect in vibration-based structural damage detection[J].Journal of Engineering Mechanics,2011,137(12):785―796.
[6]Ding Y,Li A.Temperature-induced variations of measured modal frequencies of steel box girder for a long-span suspension bridge[J].International Journal of Steel Structures,2011,11(2):145―155.
[7]Moser P,Moaveni B.Environmental effects on the identified natural frequencies of the dowling hall footbridge[J].Mechanical Systems and Signal Processing,2011,25(7):2336―2357.
[8]Wattana K,Nishio M.Traffic volume estimation in a cable-stayed bridge using dynamic responses acquired in the structural health monitoring[J].Structural Control&Health Monitoring,2017,24(4):e1890.
[9]Magalhaes F,Cunha A.Automated identification of the modal parameters of a cable-stayed bridge:influence of the wind conditions[J].Smart Structures and Systems,2016,17(3):431―444.
[10]孙利民,周毅,谢大圻.环境因素对斜拉桥模态频率影响的周期特性[J].同济大学学报:自然科学版,2015,43(10):1454―1462.Sun Limin,Zhou Yi,Xie Daqi.Periodic characteristics of environmental effects on modal frequencies of a cable-stayed bridge[J].Journal of Tongji University(Natural Science),2015,43(10):1454―1462.(in Chinese)
[11]周毅,孙利民,谢谟文,等.桥梁模态频率与运营环境作用的相关性研究[J].工程科学学报,2018,40(3):276―284.Zhou Yi,Sun Limin,Xie Mowen,et al.Correlation analysis of modal frequency variation for a bridge with operational and environmental actions[J].Chinese Journal of Engineering.2018,40(3):276―284.(in Chinese)
[12]何晓群,刘文卿.应用回归分析[M].3版.北京:中国人民大学出版社,2011.He Xiaoqun,Liu Wenqing.Applied regression analysis[M].3rd ed.Beijing:China Renmin University Press,2011.(in Chinese)
[2]Mosavi A A,Seracino R,Rizkalla S.Effect of temperature on daily modal variability of a steel-concrete composite bridge[J].Journal of Bridge Engineering,2012,17(6):979―983.
[3]He X.Vibration-based damage identification and health monitoring of civil structures[D].San Diego:University of California,San Diego,2008.
[4]Cross E J,Koo K Y,Brownjohn J M W,et al.Long-term monitoring and data analysis of the tamar bridge[J].Mechanical Systems and Signal Processing,2013,35(1–2):16―34.
[5]Zhou H,Ni Y,Ko J.Eliminating temperature effect in vibration-based structural damage detection[J].Journal of Engineering Mechanics,2011,137(12):785―796.
[6]Ding Y,Li A.Temperature-induced variations of measured modal frequencies of steel box girder for a long-span suspension bridge[J].International Journal of Steel Structures,2011,11(2):145―155.
[7]Moser P,Moaveni B.Environmental effects on the identified natural frequencies of the dowling hall footbridge[J].Mechanical Systems and Signal Processing,2011,25(7):2336―2357.
[8]Wattana K,Nishio M.Traffic volume estimation in a cable-stayed bridge using dynamic responses acquired in the structural health monitoring[J].Structural Control&Health Monitoring,2017,24(4):e1890.
[9]Magalhaes F,Cunha A.Automated identification of the modal parameters of a cable-stayed bridge:influence of the wind conditions[J].Smart Structures and Systems,2016,17(3):431―444.
[10]孙利民,周毅,谢大圻.环境因素对斜拉桥模态频率影响的周期特性[J].同济大学学报:自然科学版,2015,43(10):1454―1462.Sun Limin,Zhou Yi,Xie Daqi.Periodic characteristics of environmental effects on modal frequencies of a cable-stayed bridge[J].Journal of Tongji University(Natural Science),2015,43(10):1454―1462.(in Chinese)
[11]周毅,孙利民,谢谟文,等.桥梁模态频率与运营环境作用的相关性研究[J].工程科学学报,2018,40(3):276―284.Zhou Yi,Sun Limin,Xie Mowen,et al.Correlation analysis of modal frequency variation for a bridge with operational and environmental actions[J].Chinese Journal of Engineering.2018,40(3):276―284.(in Chinese)
[12]何晓群,刘文卿.应用回归分析[M].3版.北京:中国人民大学出版社,2011.He Xiaoqun,Liu Wenqing.Applied regression analysis[M].3rd ed.Beijing:China Renmin University Press,2011.(in Chinese)